In a prior art, a system described in JP-A-10-257482, for example, etc. are known as the image display controlling system. FIG. 4 is a configurative block diagram of an image display controlling system in a prior art. In the image display controlling system in the prior art, imaging means 41 are installed into a vehicle, and a plurality of picked-up images output from the imaging means 41 are input into an image combining means 42 to combine therein. The vehicle predictive route locus data generated by a rendering data generating means 43 to assist the driving, etc. are superposed with a combined image which was combined by the image combining means 42, then input into an arrangement controlling means 44 to decide arrangement of the images, and then output onto a displaying means.
The imaging means 41 is a CCD camera loaded on the vehicle, for example. As shown in FIG. 5, (Assume that the front side of the vehicle is indicated by the “front” in FIG. 5. This is similarly true in the following.), two imaging means 41 are fitted to pick up images in respective imaging ranges 501, 502 near left and right side mirrors, and one imaging means 41 is fitted to pick up an image in a rear center imaging range 503. The image combining means 42 combines infinite points in a rear left image 504, a rear right image 505, and a rear image 506 together as one infinite point, then applies a viewing transformation to three images to view these images from one virtual viewpoint, and then formulates a display screen 507 composed of a sheet of image by combining three images. This display can show the image picked up by three imaging means 41, particularly the road surfaces, to the driver in such a way that these images looks as if these images constitute one screen.
However, in this arrangement of these imaging means 41, their viewpoints are different between the imaging means 41 fixed on both sides and the imaging means 41 fixed on the rear center side. In other words, since positions of CCDs for picking up the image are largely different, views of three-dimensional objects that exist at boundaries of the combined display screen 507 are apparently different between respective imaging means 41. For this reason, it is impossible to assemble such objects that are originally seen as different shapes into identical objects, no matter how the virtual viewing transformation is executed. Thus, the driver feels a sense of incompatibility when the display is provided to the driver as the moving image. For example, a profile of other vehicle is changed suddenly at the boundary of the display screen 507 during when such other vehicle is moving from the rear center to the side portion.
Therefore, as shown in FIG. 6, it was considered that a plurality of imaging means 41 should be arranged to locate their viewpoints at almost same positions. In FIG. 6, two imaging means 41 pick up the image on the rear center portion of the vehicle in imaging ranges 510, 511 respectively. In this case, since their viewpoints are close and the positions of CCDs for picking up the image are almost equal, three-dimensional objects that exist at boundaries of a combined display screen 514 are viewed almost identically by the imaging means 41 respectively even when the images picked up by the left and right imaging means 41 are combined panoramically. Therefore, images of the three-dimensional objects such as the road surface, the vehicle existing thereon, etc. at the boundary or joint are connected very naturally, and thus the driver seldom feels a sense of incompatibility at the joint. Positional relationships between an own car and other cars, images of which are being picked up, in an example of FIG. 6 is shown in FIG. 7. A first car 701, a second car 702, a third car 703, and a fourth car 704 are present in order of the farthest position from own car 705. It is understood that the screen in FIG. 6 can display the image in the visual field range of about 180 degree.
The rendering data generating means 43 generates a predictive route locus 515 (e.g., a locus obtained by transferring maximum width lines onto the road surface) as the rendering data when the vehicle backs. Then, the arrangement controlling means 44 controls arrangements of the actual image which was previously adjusted and the locus to produce an image in which two images are superposed as the final display image 514.
As described above, according to the image display controlling system in the prior art, even though the imaging range of each imaging means 41 is narrow, the wide visual field can be implemented on one screen by combining the images picked up by a plurality of imaging means 41, and thus the driver's blind spot can be reduced.
However, the image display controlling system in the prior art having the above configuration has the problems described in the following. That is, in the former of the prior art, as described above, the positions of respective imaging means are largely different. Therefore, even though the images are deformed and then combined, the three-dimensional objects are still viewed to largely deform and thus not only the driver feels a sense of incompatibility but also it is difficult for the driver to know what objects are being displayed. In addition, even if the driver can know what objects are being displayed, it is difficult for the driver to understand which direction the images are in because respective images are simply pasted together two-dimensionally.
Also, in the latter of the prior art, since the images can be seen panoramically, the driver can check what objects are present in the wide visual field. However, such a problem existed that the driver is caused to hallucinate such that he or she looks at the screen in the acute visual field that is considerably narrower than 180 degree, as apparent from the image in FIG. 6, though the screen has the visual field of almost 180 degree, and therefore the driver is caused to lose a sense of direction.
For example, as shown in FIG. 7, actually the forth car 704 should come aside the driver's car essentially when the driver views the car from the rear end of his or her car at which the image is picked up, nevertheless the driver views the car in the obliquely backward direction from the driver's car.